Endrin stabilized with tribenzylamine



United States Patent 3 269 897 ENDRIN STAEILlZEli WfTH TRIBENZYLAMINEArthur W. Carlson, Crystal Lake, 111., assignor to Velsrcol ChemicalCorporation, Chicago, 111., a corporation of Illinois No Drawing. FiledFeb. 20, 1963, Ser. No. 260,050 9 Claims. (Cl. 16733) The presentinvention relates to new stable insecticidal compositions containingendrin and to the method of their preparation. This invention isparticularly concerned with stabilized endrin compositions which can bereadily formulated without undesirable auxiliary effects.

Endrin is the accepted name for the chemical 6,7-epoxy-l,2,3,4,10,10-hexachloro l,4,4a,5,6,7,8,8a octahydro-1,4,5,8 endo,endo-dimethanonaphthalene. As used herein it includes the normalcommercial product which will contain a minimum of about 95 weightpercent of the pure compound, the remainder being materials formedduring the manufacturing processing.

In the past in has become well established that endrin is a broadspectrum insecticide of significant commercial importance.Unfortunately, as has been previously disclosed, it is known that endrinis somewhat unstable and that during storage it will convert toinsecticidally inactive compounds.

Thus, in order to maintain its commercial importance it is necessary toemploy in combination with endrin a stabilizer therefor. Numerouscompounds have been suggested for this purpose with varyingeffectiveness as a stabilizer.

In the actual application of insecticidal compositions, particularlycrystalline materials such as endrin, it is necessary to formulate theactive components so as to permit adequate dispersion of the insecticideand the resulting maximum effective use thereof. Unfortunately, it hasbeen found that in the preparation of these formulations using asubstantial number of additives proposed as effective stabilizers,undesirable effects are obtained by the mixing of the components of theformulation with the stabilized endrin, effects caused by interaction ofthe stabilizer and the other ingredients of the formulation.

These adverse side reactions seriously hamper the application of theendrin containing formulation and its marketability. Not only is theprecipitate or sludge formed by reaction of the deactivatorobjectionable from the viewpoint of appearance, but it causes seriousand often fatal problems particularly the clogging of the applicationequipment.

It is, therefore, an object of the present invention to provide a meansfor the stabilization of endrin. More particularly it is an object ofthe present invention to create a procedure for the stabilization ofendrin which will cause no undesired auxiliary effects.

Further, it is an object of the present invention to devise stabilizedformulations of endrin.

Especially it is an object of the present invention to createemulsifiable concentrated endrin mixtures which are virtually completelyfree of precipitate.

These and other objects of the present invention can be accomplished bythe ensuing procedure.

It has now been found that the undesired deterioration of endrin can beprevented without the formation of undesired side reactions andresulting precipitates and sludges by using as the stabilizer for theendrin an effective amount of tribenzylamine (referred to as TBA). Bythe use of this specific material as the stabilizer for endrin it hasbeen unexpectedly found that the endrin not only will not decomposeduring storage or application but will contain no precipitate even afterformulation.

As previously mentioned, most materials having prac- Patented August 30,1966 "ice tical utility for this purpose have the unfortunatecharacteristic of forming undesired byproducts particularly when theendrin is formulated as is generally necessary prior to its ultimateapplication. This latter effect is especially pronounced during theproduction of emulsifiable concentrates of endrin since in theirformation there is necessarily employed emulsifiers. Generally, thepreferred emulsifiers contain as an essential ingredient either acalcium or a magnesium alkyl aryl sulfonate. While other emulsifiers areavailable, the emulsifiers of this classification have especially fineemnlsification properties which make them preferable commercialarticles.

By an emulsifier containing a calcium or magnesium alkyl aryl sulfonateit is understood that this means that the emulsifiers can and normallydo contain other ingredients since most commercially used emulsifiersare a blend of various ingredients. In these mixed emulsifiers thecalcium or magnesium sulfonate is an anionic active agent. Since thesematerials are special blends the variety of components is large as isthe specific proportions of the ingredients. The commercially availableemulsifiers are sold under the trademark of the manufacturer, whogenerally jealously guards the make-up of his emulsifier from the world.Accordingly, it is not possible to define these materials with precisionother than as to the overall type or classification and certainingredients thereof determined by arduous analysis or from the limitedamount of information supplied by the manufacturer. For the purpose ofthe present invention it is only necessary that the emulsifier containas an active ingredient calcium or magnesium, usually as the sulfonate,which generally are present as a calcium or magnesium alkyl arylsulfonate. It is this component which causes the undesired sludge orprecipitate when in contact with many of the materials proposed asendrin stabilizers.

In accordance with the present invention endrin is contacted with astabilizing amount of tribenzylamine. Since both materials occur assolids at room temperature, this can readily be performed by mixing theendrin and the tribenzylamine in standard blending equipment.

No difficulty has been incurred in obtaining uniform distribution of thetribenzylamine by dry blending techniques and therefore no need existsfor using other more complicated procedures such as by the use ofsolutions, although they can be employed. Accordingly, adequateincorporation of the tribenzylamine is accomplished by the simplest ofknown procedures.

Extremely small quantities of tribenzylamine have been found toaccomplish the requisite effect. For example, quantities oftribenzylamine as low as 0.01 weight percent of the endrin are quiteeffective in producing a stable endrin product. Naturally the termstable is somewhat relative, since it will depend on the conditions ofstorage and use, as well as the amount of product degradation which istolerable. While as indicated above, as low as about 0.01 weight percenttribenzylamine will be suitable for effective stabilization, in certaininstances where more extreme conditions may be encountered by the endrinit can be suitable to use at least about 0.05 weight percent based onthe endrin content. No practical advantage is obtained by usingexcessive amounts of tribenzylamine for the present purpose, althoughamounts up to about 0.25 weight percent can be used to insure againstthe most extreme adverse conditions and for prolonged storage times.

In order to determine the stabilization of endrin by the incorporationof tribenzylamine the following experiments were performed:

Example I A solution of endrin (10.0 grams; 97% assay) dissolved inhexane was added to a solution (2 ml.) of tribenzylamine (0.02 gram)dissolved in pentane. After the addition the solvent was removed fromthe solution and the residue further stripped under a pressure offifteen millimeters of mercury for ten minutes. The residual solid fromthis operation was powdered and the powdered material was placed intotwo jars. One of the capped jars was placed in an oven held at atemperature of 120 F., and the second jar was placed in an oven held ata temperature of 200 F. In order to have a control on these experiments,endrin from the same batch (97% assay) but containing no additives wasplaced in tWo capped jars similar to those used for theendrin-tribenzylamine blends. The jars were kept in the ovens for fixedtime periods at which times the percent endrin was determined by meansof infrared analysis with the following results:

Time (Months) Example 2 Tribenzylamine (7.5 pounds) was added to endrin(4,800 pounds; 97% assay) and blended therewith for about one hour. Atthat time the product was drummed and the drums analyzed for percenttribenzylamine. The percentage of tribenzylamine as determined bytitration with perchloric acid in chloroform-dioxane was found to varybetween 0.14 and 0.16 percent by Weight. A sufficient sample of materialwas taken from a drum of the product which analyzed 0.16 weight percenttribenzylamine. Ten grams of this product was mixed with grams of endrinused initially but which did not contain stabilizer so as to prepare astabilized endrin product which contained 0.08 weight percenttribenzylamine. Five grams of the product (0.16% tribenzylamine) wasmixed with grams of the unstabilized endrin to prepare a productcontaining 0.04 weight percent tribenzylamine. Finally 3 grams of thestabilized endrin containing 0.16 weight percent were mixed with 21grams of the original unstabilized endrin so as to prepare a stabilizedendrin product containing 0.02 weight percent tribenzylamine. Thebottles containing the respective samples were then placed in an ovenheld at a temperature of 200 F. At the end of 35 days they were analyzedfor percent endrin as follows:

Percent Percent Percent Tribenzylamine Endrin initial Endrin at 35 daysafter a month at which time none of the unstabilized control was inexistence.

In order to determine the characteristics of the emulsifiableconcentrates prepared from the stabilized endrin product of the presentinvention, and from stabilized endrin products using other stabilizers,a series of experiments were performed to determine the amount ofsludge, if any, obtained therefrom as follows:

Example 3 Endrin (20 grams; 97% assay) dissolved in a stock solutionml.) was placed into each of 10 pear-shaped centrifuge tubes having 1.00ml. graduated tips. The stock solution was composed of two emulsifiers,Sponto 221 (40 grams) and Sponto 217 (10 grams) dissolved in heavyaromatic naphtha solvent (730 grams). Sponto 221 and Sponto 217 aretrademarks for emulsifiers of the anionic-nonionic class wherein acalcium alkyl aryl sulfonate is present as an anionic portion. Into eachcentrifuge tube was inserted 1.00 ml. of a solution of one of the amineslisted below dissolved in a heavy aromatic naphtha, such that the amineconstituted 0.20 weight percent of the endrin. After twenty four hoursthe tubes were centrifuged for identical time periods and the volumes ofsludge in each tube were compared as follows:

Percent by volume Amine: of sludge No amine 0.05 Tribenzylamine 0.05Hexamethylenetetramine 2.3 Triethylamine 4.0 Tri-n-propylamine 2.5Diethylamine 5.0 Morpholine 3.0 Benzylamine 3 .0 Isopropylamine 8.0Ethanolamine 3.5

Example 4 The procedure used in Example 3 was repeated using varyingamounts of tribenzylamine including relatively large amounts. Thepercentage of sludge formed was measured after 45 hours and found to beas follows:

Percent by volume Percent tribenzylamine: of sludge Example 5 Theprocedure of Example 3 was repeated using a variety of endrin productsand determining the percentage of sludge two days after preparation ofthe mixture and after they have been centrifuged. (The endrin productscontaining tribenzylamine were prepared in accordance with the procedureof Example 2.)

Percent by volume Percent tribenzylamine: of sludge It should be notedthat the amount of sludge formed from endrin stabilized withtribenzylamine is approximately equivalent to that obtained when usingendrin containing no stabilizer. Since endrin containing no stabilizerlacks the desired stability requisites for many applications, thiscomparison is made solely to show that the tribenzylamine does notcontribute to the formation of the undesired sludge. Furthermore, it canbe readily observed that the amount of sludge formed when using otheramine stabilizers is from about 45 to 160 times the volume of sludgeformed when using tribenzylamine as the stabilizer.

The stabilized endrin product prepared in accordance with the presentinvention can be used by all of the methods available for theapplication of insecticides and can be formulated into wettable powders,granulars, dusts, solutions, etc., using the various inert carriers,liquid and solid, and the additives, i.e., stickers, wetting anddispersing agents, commonly required for the production of suchmaterials.

As previously indicated, this present stabilized endrin product isparticularly useful in the production of emulsifiable concentrates sinceit will not cause the formation of a sludge or precipitate of any typeas is produced by stabilized endrin products containing other knownstabilizers, including other known amine stabilizers. These emulsifiableconcentrates can be prepared by the established procedure such as thefollowing:

Example 6 Emulsifier was Weighed into an Erlenmeyer flask and solventadded thereto. After swirling the flask to dissolve the emulsifier,endrin (20 grams) was added and the flask was placed on a hot plate andstirred to dissolve the endrin. A tribenzylamine solution (1 ml.containing 30 milligrams of TBA) was added and poured into thecentrifuge tubes. In order to determine the sludge content the tubeswere centrifuged 45 hours later. The specific emulsifiers, and solventsused and the resulting sludge contents were as fol-lows:

Emcol is a trademark of the Witco Chemical Company who describe Emcol85X, 300X and Emcol H500X as blends of oil soluble calcium sulfonateswith polyoxyethylene ethers. Triton is the trademark of the Rohm andHaas Company who describe Triton X172 and Triton X152 as blends of alkylaryl polyether alcohols with organic sulfonates. Atlox is the trademarkof the Atlas Chemical Company for a series of nonionic-anionicemulsifiers composed of blends of polyoxyethylene derivatives andcalcium alkyl aryl sulfonates. Toximul is the trademark of the StepanChemical Company. Toximul H and Toximul L are blends of calcium alkylaryl sulfonates and polyglycol ethers. Makon is the trademark of theStepan Chemical Company who describe Makon 10 as alkyl phenoxypolyoxyethylene ethanols.

All of these emulsifiers contain calcium. While in the foregoingexamples emulsifiers containing calcium were employed to show thebeneficial results obtained by using tribenzylamine as the stabilizerfor endrin, magnesiumcontaining emulsifiers could have been equivalentlyutilized as they cause the same precipitate problem.

Furthermore, the present invention is not limited to the formulationsshown in the foregoing examples as it is already known that endrin canbe formulated into many other emulsifiable concentrates by varying theidentity of the emulsifiers and solvents and the concentrations of theingredients. See for example U.S. Patent No. 2,872,368 entitledEmulsifiers and Toxicants Containing the Same. By means of the presentinvention stable endrin formulations can be obtained without the problemof sludge or other precipitate formation.

I claim:

1. A stabilized endrin composition which contains endrin and astabilizing amount of tribenzylamine.

2. A stabilized endrin composition which contains an insecticidallytoxic amount of endrin and a stabilizing amount of tribenzylamine.

3. A new composition of matter which comprises endrin and a minimum ofabout 0.01 weight percentthereof of tribenzylamine.

4. A composition of matter which comprises endrin in combination withtribenzylamine in a quantity from about 0.01 to 0.25 weight percent ofthe endrin.

5. An emulsifiable endrin concentrate which comprises endrin, endrinstabilizing amount of tribenzylamine, emulsifier and solvent therefor.

6. An emulsifiable concentrate which comprises endrin, tribenzylamine inan endrin stabilizing quantity, enert solvent therefor and emulsifiercontaining as an essential portion a metal selected from the groupconsisting of calcium and magnesium.

7. An emulsifiable concentrate which comprises endrin, tribenzylamine inan endrin stabilizing amount, an inert solvent therefor and anemulsifier containig as a component a sulfonate selected from the groupconsisting of calcium sulfonate and magnesium sulfonate.

8. An emulsifiable concentrate which comprises endrin, tribenzylamine inan endrin stabilizing amount, an inert solvent therefor, and anemulsifier containig as a component av sulfonate selected from the groupconsisting of calcium alkyl aryl sulfonate and magnesium alkyl arylsulfonate.

9. An emulsifiable concentrate which comprises endrin, tribenzylamine inan endrin stabilizing quantity, an inert solvent therefor, and anemulsifier containing as a essential component calcium alkyl arylsulfonate.

References Cited by the Examiner UNITED STATES PATENTS 2,043,257 6/1936Missbach 260-6525 2,658,017 11/1953 Marhofer 16730 2,768,181 10/1956Bellin et a1. 260-348 3,056,722 10/1962 Trademan et a1. 167--33 JULIANS. LEVITT, Primary Examiner.

GEORGE A. MENTIS, Assistant Examiner.

1. A STABILIZED ENDRIN COMPOSITION WHICH CONTAINS ENDRIN AND ASTABILIZING AMOUNT OF TRIBENZYLAMINE.